This invention relates generally to electro-optical devices and, more specifically, to electro-optical devices employing liquid crystals for the optical storage of data. Optical data storage is effected by altering the orientation of the liquid crystal molecules within a liquid crystal cell. The orientation affects the polarization of light passing through the cell and therefore provides a technique for reading the data optically. In a number of applications there is a need to convert data from electrical form to an optical form in which the data will be displayed or further processed. One such application is in optical computing systems, in which data elements in optical form are rapidly processed by optical logic elements.
Processing data in optical form is a particularly attractive approach if the data can be automatically scrolled across an optical matrix, since many mathematical manipulations involving matrices can be performed more simply if the data elements remain in matrix form. The conventional electronic processing approach to matrix processing involves retrieving data elements from an electronic memory matrix, and storing intermediate and final results in the same or a different memory matrix. If the matrix data elements are stored in optical form, two optical data matrices can be directly interacted, in optical form, to produce a mathematical result. Moreover, if one matrix can be shifted or scrolled, a matrix multiplication can be performed directly, without converting the data back into electrical form.
Another application for a scrolling optical storage device is the display of data. Conventional liquid crystal displays employ matrix (x-y) addressing methods to enter the data, whereby each liquid crystal element is defined by a unique combination of an x-axis address and a y-axis address, both of which must be selected to access the element. Such displays often employ active devices, such as transistors, in the display structure. When displayed data, which may be textual characters, are scrolled in a conventional liquid crystal display, the data elements have to be rewritten into appropriate locations for each incremental scrolling movement. This requires relatively complex circuitry and is both costly and inconvenient.
Therefore, there is a need in optical computing and related applications for a spatial light modulator that has scrolling capability. The present invention is directed to this end.